The effects of recreational drugs and alcohol. Some types of recreational drug may trigger paranoia, such as cocaine, cannabis, alcohol, ecstasy, LSD and amphetamines. This may happen particularly if you’re already feeling low, anxious or experiencing other mental health problems. However, researchers still aren’t sure whether recreational drugs directly cause paranoia, or if people who experience paranoia are also more likely to use recreational drugs. Certain steroids taken by athletes, and some insecticides, fuel and paint, have also been associated with paranoia. Drinking alcohol and smoking may also stop medication from effectively treating your symptoms. See our pages on recreational drugs and alcohol for more information.